The specification and drawing of U.S. Pat. No. 5,087,975 issued Feb. 11, 1992 to R. W. Citta et alii and entitled VSB HDTV TRANSMISSION SYSTEM WITH REDUCED NTSC CO-CHANNEL INTERFERENCE are incorporated herein by reference. Citta et alii describe a television signal transmission signal for broadcast television comprising a suppressed carrier, a VSB signal having respective Nyquist slopes at the lower- and upper-frequency edges of a television channel with 6-MHz bandwidth, the center frequency of the Nyquist slope at the lower-frequency edge of the channel being substantially coincident with the frequency of the suppressed carrier, and a pilot signal in quadrature relation with the suppressed carrier. The television signal transmission signal is susceptible to cochannel interference from NTSC television signal with a video carrier 1.25 MHz above the lower-frequency edge of the channel, a color subcarrier 3.58 MHz above the video carrier in frequency, and an audio carrier 0.25 MHz below the upper-frequency edge of the channel. The suppressed carrier is modulated by an N-level digitally encoded signal having a sample rate f.sub.s substantially equal to three times the NTSC color subcarrier frequency, with the frequency of the suppressed carrier being closer to the lower-frequency edge of the channel than the co-channel NTSC picture carrier by an amount equal to about f.sub.s /12. The received signal is demodulated by a synchronous detector in response to the received pilot signal and interfering NTSC beat components are attenuated by a linear filter having notches at f.sub.s /1, at 5 f.sub.s /12 and at f.sub.s /2.
A Digital Television Standard published Sep. 16, 1995 by the Advanced Television Systems Committee (ATSC) specifies VSB signals for transmitting digital television (DTV) signals in 6-MHz-bandwidth television channels such as those currently used in over-the-air broadcasting of National Television System Committee (NTSC) analog television signals within the United States. These VSB signals differ from those described by Citta et alii in that each uses a pilot signal in phase with its suppressed carrier, rather than in quadrature therewith. These VSB signals each comprise a vestigial sideband near the lower upper-frequency edge of the television broadcast channel and a full sideband extending upward in frequency therefrom to the upper-frequency edge of the channel.